Reduction gearing



B. F. rSCHMIDT AREDUCTION GEARING April 25, 1950 2 sheets-sheet` 1 Filed Aug. a, 19444 APfil 25, 195o Filed Augl 8' 19444 'Ilv Illum B. F. SCHMIDT REDUCTION GEARING il i.'

INVENTOR Patented Apr. 25., 149510 UNITED STATES PATENT OFFIC REDUCTION GEARING Benjamin F. sehmiat, Les Angeles, Calif. e Application August 8, 1944, Serial No. 548,517

9 Claims. (Cl. 74-789) My invention relates to reduction gearing and has particular reference to a gearing which may i i to provide for a high speed and a low speed transmission which may be readily selectable, dependent upon thencharacter of thework to be done. For example, in many applications of small industrial electric motors it is desirable that the motor operate tol produce one speed of transmission for'the driving of certain portions of a machine while other portions of the machine are required to beV driven at a'different speed but coordinated with the speed of the first drive.

` It is therefore an object of my invention to provide a gear reduction unit which may be readily employed for the purposeof producing a difierentialbetween two transmissions to permit the *same motivepower means tov provide two different speeds of transmission.`

Another object of my invention is to provide a reduction gearing of the character described, which may be readily and simply manufactured andrnay be embodied as an integral part of the assembled prime mover or motor.

Another object of myrinventionis to provide a reduction gearing fof the characterwdescribed which is readily adapted for use in either a power or alchain hoist to permit the application of `force through a substantiallydirect drive for the purpose of bringing the hoisthook into taut relation with the load and thereafterthe power may be applied through a reduced gearing for the purpose of raising the hook and the load from that point. Y

- Other objects and advantages of my invention will be apparent from a study of the-following specications, read in connection with the accompanying drawings, wherein Fig. 1 is vertical sectional `view taken through a reduction gearing constructed in accordance with my invention and illustrated as being assembled asfanintegral part of the end-bell of an electric motor; f Fig. 2 is a transverse sectional view taken along line II-II of Fig. 1; l 'i Fig. 3 is a detail view of one of the transmission pinions which I employ in' my reduction gearing;

Fig. 4 is a detail view of the supportingfr'ame member for carrying the pinions; Y'

Fig. 5 is a detail View 'of a 'modified'form of Y pinion which `may be kemployed inmy reduction gearing; Y

Fig. 6 is a vertical sectional view of a modified application of the same form of reduction gear as that illustrated in Figs. 1 through 4 but showing the same as applied to a chain actuated hoist; and

Fig. 7 is a vertical sectional View taken along line VII- VII of Fig. 6.

Referring to the drawings, I have 'illustrated my invention as being applied to an electric motor I, the housing 2 of which is provided with an end flange 3, to which may be attached the usual endbell, The armature 4 of the motor is illustrated schematically as operating in conjunction with the field poles 5 surrounded by exciting coils 6 as in the usual electric motor construction. The armature 4 is provided with a shaft l, from which power arrived fromthe motor is to be taken off.

In place of the usual end-bell of the motor providing merely, a bearing for the shaft 1, I substitute a special end-bell 8, which end-bell has an internally formed recess 9 carrying a bearing I and providing a suitable housing within which may be received the reduction gearing constructed in accordance with my invention. H

The reduction gearing comprises essentially a tubular drive shaft II provided, as indicated at I2, with worm teeth intermeshedwith a pair of pinions I3 and I4. These pinions are rotatably mounted upon stub shafts I5 upon a supporting structure I6, illustrated particularly in Fig. 4, in such manner that rotation of the tubular shaft 'I relative tothe supporting frame I6 will cause the pinions to rotate about their stub shafts I5.

By referring particularly lto Figs. 2 and 3, it will be observed that each of the pinions is provided with an extension, which in turn has formed upon it a conically shaped worm`thread I1 adapted to mesh as indicated in Fig. 2 with internally formed teeth I8 upon a ring I9. Thus as the pinions I3 and I4 are rotated they will cause rotation of the ring gear I9. However, by securing the ring gear la against rotation relative to the end-bell of the motor, as by a, key 20, the result ofthe rotation of the pinions I3 and I4 will be toV cause the supporting frame I 6 to rotate relative to the end-bell 8 and relative to the motor shaft l. The relative rates of rotation of the motor shaft and the frame I'6 will be greatly different, the eliect being to produce a diierential motion between these two shafts. By properly selecting the number and pitch of the worin teeth upon the drive shaft I I and the diameter and pitch of the pinions I3 and I4 and also the pitch of the worms I1, substantially any desired relative speeds of ro-` tation may be obtained between the motor shaft and the frame.

As will be observed from an inspection of Figs. 1 and 4, the frame I6 is provided with a forwardly extending portion 65a which provides a sleeve shaft from which power may be taken off.

Thus by providing a pulley 2l upon the sleeve shaft H keyed thereto as indicated at 22 (the sleeve shaft H being keyed as indicated at 23 to the motor shaft 1),"the pulley?! will be operated at the normal 'rate of rotation of the motor. By providing a second pulley 24, keyed as indicated at 25, to the sleeve shaft formed by the extension Ia, the pulley 24 may be rotated at some different rate of speed dependent upon the selection of the gearing as described above.

1f desired, the frame I5 may vbe provided with both radial and thrust bearings indicated'at' 25, 2l' and 25 to reduce the friction of rotation of this frame relative to the sleeve shaft i i and the End-bell in which it operates, the lbearings 2l 'and Vloeing preferably held in vplace by spring wash- -ersa29 Asnapped into grooves formed in the endbell-and the "sleeve shaft l i, respectively. Similarly, the main bearing l for the motor shaft mayfbe 'held in -place by means'of a snap ring 3o seated in a radial groove 'formed upon the endbellV structure.

In view of the fact that there will undoubtedly beconsiderable bending thrust exerted upon the extreme outer end of the extension ia of the frame, 'I prefer to `provide a needle roller bearing -32iinterposed between the sleeve shaft i l and the 'extension Ita. Likewise needle bearings S3 and 54 4'may be provided for each of the pinions 43 and I4, 4as illustrated in Fig. 2, while a thrust Hearing-35 'may be provided also for each of these bearings.

YA. novel manner in Whicn the rstub shafts I5 -rnay'be secured in the supporting frame' i6 `is yillustrated in Fig. 2 as comprising forming laterally extend-ing bores completely through the piece of IIn'etal or othen'material of Ywhich the frame is made, into which the stub shafts l5 may bein- 'ser'ted'fand held in place by cross pins "-By employing the recess 9 in lthe end-bell o'f motor as the housing into which the reduc- 4ti Vifge'aringmaybe inserted; it will he appar-ent 'that'the-entirestructure Ymay be inserted or relr'ho'ved as a unit by merely reinovizigitheend washerl which-iseniployed toretain the 'as- 'sembly withinlthe recess. This facilitates repair permitting*theready removal of any"red'uc -tion gearing which mayA be out of order and fthe Aifnrnediate su'bstitutionof va` duplicate 'assembly with aminimum of 'effort andlossof time, 'further facilitates the initialassenibly 'by 'permitting the entire gear unit'to'be made up as 'an `assemblyindependent ofthe rhotoraid Ythen'to b'eassembled upon the rmotor merely byi'nsertion ihlthe're'cessan'd securing thewasherto 'the endbell.

when the reduction gear is to be efr-proyector drivinga relatively large ring 4gear upon which great 'loads a'reirnposed'l prefer to use -aldoiib'le worm ended pinion i3V as shown iLrFig. l5,l which permits the distribution "of thedriving forces 'over' additional areasfof gear teeth.` v `In Figsf'and'vhave illustrated a modified application of the same essential reduction gearingstructure'as ythat illustrated in Figs. 1' through 4,;the adaptation being to a chain hoist wherein thehoist is supported =upon a suitable hook '45 which engages a yoke-likefrarne 4l.v The frame `4`| 'has 'a transverse bore 42 formed therein, into which is inserted the pinion supporting frame 43,

corresponding in all essential respects to the frame i6, heretofore described.

The frame 43 is provided with a longitudinal bore 44, through which extends a power shaft 45, one end of which may be secured to a pulley 46 provided with chain sprocket recesses 4l or, as will be understood by those skilled in this art, the shaft'45 -rnay bejcoupled in any suitable inanner to'ffa'n electric oidther type of motor which will cause rotation of the shaft 45.

The shaft 45, like the sleeve shaft Il, is provided with a worm thread 48 which meshes with a pa'irof pinions 49 and 50, respectively, these vpinions `being frnounted upon stub shafts 5I mounted in the frame 43, in the same manner as lwas 'fdescribedi'foifthe stub shafts i4. Again the pinions 4x9 and 5G are provided with extensions which are formed as conical worms 52 meshing with internal teeth 53 upon a ring gear 54. in this frm of Vrrryrn'y'znnon,"trfering gear sa is not fi'ii'ed against 'r tation but isemployed as the powitrahsinl'ittifng iportion 'of 'the 'gearing Vas by providing uponfits i'terir a vradially extending pair of Yflang's'Sli whichform a 'chain sprocket over which the l'io'istin'g 'chain of the hoist extends. I

Thusbyrotating Ythe lsh`aft45,` either by means o-f the Ypu'lleyfil 6r ainotor (not shown), the resultant rotation ofthe pinions -49`will cause 'a 1'0- tation 'of the ring "g`e'ar"53 "at a 'much "reduced speed and "therefore with great mechanical advantage. V

Again, fas with the forin of "the gearing illustrated inFigs. l through 4,'each of the parts may besUitabIy 'suppoted'in'rollen thrust or needle bearih'gs'as Yillustrated iirligs. 6 and 7.

In 'order to permit the ready'and rapid movement of thehistfnghook a't the end of the hoisting chain, Ifpeferto 'provide a means for selectively perihittinglrot'atioh of the pinion supporting frame 43. This'ihayber'eadily accomplish'e'd by providing `a`pin`56 'slidable through a vertically extendin'gopenin'g 5T 'in' one -of the legs of rthe fyo'lfe, the upper nd 'ofthe pin 56 being adapted' to ll'iera radially extending socket `v58 formed in the f`r`arii'efl3.l Thel'pin' Yls'normally urgedjupwaruiyby'fnenstra' spring 5a but may b'vvthdlawn' l/l're,f` it'is 'desired byy 'rne'ans of a1 ,chaine or pali-'eers' so.

' vThus if 'thepinis disengaged fromthe bore 5 8` and "thefpulley 41 iotjated,"th'e relative fricti'onhetw'enthe p' ts'vvill' cause'gear 53 "to be rotated at'th'e sfar'ne v edasthe"s'haft"45 until a vload isiplarcedru nfthe'hoisting chain. 'When this occursit'he hoisting hook and chairr'are then in a substantial`y taut relation with respect to the load that istolbehistda'dreleas'efofthechain 50 will f-per'nit'the nv 55 to be? 'urgediipwardly acains-tthesurffac `offthe"'frani'eV 43. Thereafter rotation o-f the shaft'45-'will'vcauseitheiframe 43 to "rotate-until tl'eflore=`58lis i'ealigned withthe pin'56and the'lpi'n p'e'zim'itte'd "to reenter the socket "58. -At this ftiine thefpartsvare'then in their locked upre'latiohsoithat furthermovement of the shaft 45 will cause rot'a'tioh I-of ''the ring gearfS iat the reduced-speed and' with the mechanical advantage necessaryto lift the load. f Ifv desired, -afchainguard' 5| may bek mounted upon the yokeA frame-'41, asfby 'means lof screws 62, thevguardopreferably beingformed' s'o asto extend immediatelyiabovefthe Vperiphery of the pulley orsprocket v46 -so astoV prevent the chain fromybeing Yfinadvertervitly iremoved therefrom. An extension arm 63, which may be formed integrally with the guard 6l, is adapted to extend across theyokeimmediatly abovathe periphery@ of the; chain 4sprocket 55 to perform a similar function for thisgsprockeavlthe extreme end of theextension arm 63 beingsecuredin any suit-y able manner .as by means of a screw 64.

It lwill be observed from the foregoing descripf'W on extend substantially parallel with the longi-` tudinal axis of the ring, gear, facilitating the construction of such gear and providing a minimum amount of friction with the worm IlV on the pinion.

It will be apparent from the foregoing that I have illustrated a' reduction Vgearing which is extremely simple in its construction, which may be readily manufactured and assembled in mass production, and which provides for a substanti ally unlimited relation between the operating speeds of a driving and a driven member.

While Ihave shown and described the preferred embodiment of my invention,v I do not desire to belimited to any of the details of `construction shown and described herein, except as provided in the accompanying claims.

i 1; In a reduction gear unit, the combination of: an inner shaft having a worm thread thereon; a frame member surrounding said shaft; a ring gear member surrounding said frame member and having internal gear teeth; means mounting said members for relative rotation about ,the longitudinal axis of said shaft and mounting one of said members for rotationv relative to said shaft; a,f pair of gears'mo'unted for rotation on said frame member onA opposite .sides of said shaft, each of said gears comprising a worm' Wheel meshed with said worm thread and having a cone shaped extension extending beyond said Worm wheel and carrying a worm thread meshed with said internal gear teeth; means for holding one of said members stationary; and power takeoff means connected to the other of said members.

2. In a reduction gear unit, the combination of: an inner shaft having a worm thread thereon; a frame member surrounding said shaft; a ring gear member surrounding said frame member and having internal gear teeth; means mounting said members for relative rotation about the longitudinal axis of said shaft and mounting one of said members for rotation relative to said shaft; a pair of gears mounted for rotation on said frame member on opposite sides of said shaft, each of said gears comprising a worm wheel meshed with said worm thread and having a cone shaped extension extending beyond said worm wheel and carrying a worm thread meshed with said internal gear teeth; means for holding one of said members stationary; power takeoff means connected to the other of said members; and a second power takeoff means connected to said shaft.

3. In a reduction gear unit, the combination of: an inner shaft having a worm thread thereon; a frame member surrounding said shaft; a ring gear member surrounding said frame member and having internal gear teeth; means mounting said members for relative rotation about the longitudinal axis of said shaft and mounting one of said members for rotation relative to said shaft Aincluding an anti-friction bearing interposed be,-

tween Said `frame member and Said-Shaft; apair ofgearsmounted for rotationon said frame member on opposite sides of said shaft, each of said gears comprising a worm `wheel meshed with said 5 worm thread and having a cone shaped lextension `extending beyond said wormv wheelwand carrying a worm thread meshed with said irri- ;l

ternal gear teeth; means for holding one of said members stationary; and power takeoff means lqiconnected to the other of said members.

4. In a reduction gear unit, the combination of: anl inner shafthaving a worm thread thereon; a frame member surrounding said shaft; a ring gear member surrounding said frame member and having internal gear teeth; means mountsaid frame member on opposite sides of saidwith said internal gear teeth; means for holding.

.a frame member surrounding said shaft; a ring gear member surrounding saidframe member.

Acone shaped extension extending beyond said "worm wheel and carrying a worm thread meshed ing said members for relative rotation about the longitudinal axis of said shaft and mounting one of said members` for rotation relative to said,

shaft; apair of gears mounted for rotation on shaft, each tof said gears comprising a worm wheel meshed withesaid Worm thread and having a cone shaped extension extending beyond said ,Y

Worm wheel and carrying a worm thread meshed` said rring gear member stationary; and power takeoff means connected to said frame member. 5. In a reduction gear unit, the combinations,

of an inner shaft having a worm thread thereon;

and having internal Vgear teeth; means mounting said members for relative rotation about the s longitudinal axis of said shaft and mounting one "shaft; a pair of gears mounted for rotation on said frame member on opposite sides of said shaft, each of said gears comprising a worm wheel meshed with said worm thread and having a mounting said members for relative rotation about the longitudinal axis of said shaft and mounting one of said members for rotation relative to said shaft; a pair of gears mounted for rotation on said frame member on opposite sides of said shaft, each of said gears comprising a Worm wheel meshed with said Worm thread and having a cone shaped extension extending beyond said worm wheel and carrying a worm thread meshed with said internal gear teeth;

means for holding said ring gear member stationary; power takeoff means connected to said frame member; and a second power takeoff means connected to said shaft.

7. In a reduction gear unit, the combination of: an inner shaft having a worm thread thereon;

a frame member surrounding said shaft; a ring gear member surrounding said frame member and having internal gear teeth; means mounting said members for relative rotation about the v0 longitudinal axis of said shaft and mounting one of said members for rotation relative to said shaft; a pair of gears mounted for rotation on said frame member on opposite sides of said shaft, each of said gears comprising a worm wheel meshed with said worm thread and having a of said members forrotation relative to said,

gse-gasa" `said members for relative rotation about the longitudinali axis ofsaid shaft andmounting one of :said members yfor rotationrelative to said shaft; a pairof'lgears mountedffor 'rotationjon said :frame 'member on opposite sidesjof A said shaft, each of said gears comprising va worm Wheel meshed withsaid worm thread and having a cone shapedexten'sion extending beyond said worm Wheel and carrying a worm thread meshed with said1in`t`ernal'gear teeth; power takeoff means connected to'one ofsaid members; and releasable `means ffor normally holding the other of said'member stationary, whereby when said releasable means is released rotation of said shaft will'driveboth of said members at the same speed as said lshaft and When said 'releasable means is engaged with said other member said one member'will'b'e rotated at a predeterminedbut different speed relative to said shaft.

9. In a reduction gear unit, the combination of: an'inner shaft having a worm thread thereon; a frame -'member surrounding said shaft; a ring gear member surroundingsaid frame member and having internal gear teeth; means mounting 'said members for relative rotation about Vthe longitudinal axis of said shaft and mounting one of said members for rotation relative to (said shaft; a pair of gears mounted for rotation on "said-frame "menibfon v'opposite sides of isaid' sliaftjeach of 'said fge'ars y"comprising a worm"v'vhee1 meshed withsaid 'worm 4thread' and having 'a' cone shapedextension extending beyond said Worm `Wheel and j carrying fa Worin thread meshed Withfsad internal 'gear teeth; pov'ver takeoff meansv connected to said ring rgear member; Yand 'releasable l means for normally holding said frame"1nember stationary, whereby A10 "when said releasablefmeans is released rotation of said shaft will drive both of said membersat thesamespeed as said shaft vand when'said' releasable means is engaged `Wth said frame member "said-'ringfg'ear member will be rotated'ata predetermined jb'ut'd'iferer'it speed relative to said shaft.

BENJAMIN F. SCHMIDT.

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